text:
Agriculture worldwide faces daunting challenges because of increasing population growth and changing food consumption patterns, natural resource scarcity, environmental degradation, climate change, and global economic restructuring. Yet, at the same time, there are unprecedented hopeful changes and opportunities for the future, including a remarkable emergence of innovations in farming practices and systems and technological advances that have generated promising results for improving agricultural sustainability and an increase in consciousness and concern by consumers about the sources of their food and how it is produced. One of the first comprehensive reports on the scope and importance of systems approaches to improve sustainability of agriculture was documented in the National Research Council report Alternative Agriculture (1989b). The report analyzed and described the economic and environmental results of agricultural practices that could improve sustainability being developed and used by a small subset of U.S. farmers in the second half of the 20th century, and it helped to legitimize an approach to agricultural-systems research that had previously been considered nonscientific. Many so-called alternative practices at that time (integrated pest management, no-till farming, and cover crop planting) are now used by some farmers in mainstream agriculture.
Despite the potential benefits of farming practices and systems that improve sustainability, their adoption is far less widespread than society might want. One reason for the low rate of adoption is because of social, economic, and policy incentives that discourage fundamental changes in farming systems. Another reason is that some of those practices have tradeoffs so that they might provide benefits in one aspect and negative consequences in another. The movement toward improved sustainability could be hampered by society's lack of common agreement on which objectives are the highest priority and how tradeoffs should be managed.
Since Alternative Agriculture was published, many changes have been made in how farmers farm. While incremental approaches offer movement toward sustainability, such approaches might not tackle fundamental problems. Systemic changes and multiple paths will also need to be pursued. Indeed it can be argued that sustainability is the process of
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Understanding Agricultural
griculture worldwide faces daunting challenges because of increasing population
growth and changing food consumption patterns, natural resource scarcity, envi-
ronmental degradation, climate change, and global economic restructuring. Yet,
at the same time, there are unprecedented hopeful changes and opportunities for the fu-
ture, including a remarkable emergence of innovations in farming practices and systems
and technological advances that have generated promising results for improving agricul-
tural sustainability and an increase in consciousness and concern by consumers about the
sources of their food and how it is produced. One of the first comprehensive reports on
the scope and importance of systems approaches to improve sustainability of agriculture
was documented in the National Research Council report Alternative Agriculture (1989b).
The report analyzed and described the economic and environmental results of agricultural
practices that could improve sustainability being developed and used by a small subset of
U.S. farmers in the second half of the 20th century, and it helped to legitimize an approach
to agricultural-systems research that had previously been considered nonscientific. Many
so-called alternative practices at that time (integrated pest management, no-till farming,
and cover crop planting) are now used by some farmers in mainstream agriculture.
Despite the potential benefits of farming practices and systems that improve sustain-
ability, their adoption is far less widespread than society might want. One reason for the
low rate of adoption is because of social, economic, and policy incentives that discourage
fundamental changes in farming systems. Another reason is that some of those practices
have tradeoffs so that they might provide benefits in one aspect and negative consequences
in another. The movement toward improved sustainability could be hampered by society's
lack of common agreement on which objectives are the highest priority and how tradeoffs
should be managed.
Since Alternative Agriculture was published, many changes have been made in how
farmers farm. While incremental approaches offer movement toward sustainability, such
approaches might not tackle fundamental problems. Systemic changes and multiple paths
will also need to be pursued. Indeed it can be argued that sustainability is the process of
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constantly adapting farming or food systems to meet clearly articulated and desired out-
comes in a robust and resource-efficient manner that also reflects social responsibility.
With the support of the Bill and Melinda Gates Foundation and the W.K. Kellogg
Foundation, the National Research Council convened a committee to study the science
and policies that influence the adoption of farming practices and management systems
designed to reduce the costs and unintended consequences of agricultural production. (See
Box 1-1 for the statement of task.) To address the statement of task, the committee solicited
input from many experts in academia and federal agencies in a series of open meetings and
workshops, in addition to drawing on members' expertise. Two sets of case studies were
used to examine farming systems that address those concerns and to explore the factors
that affect their implementation, economic viability, and success in meeting environmental
and other goals of sustainability.
This report reviews the state of knowledge on farming practices, technologies, and
management systems that have the potential to improve the environmental, social, and
economic sustainability of agriculture and discusses the tradeoffs and risks that might pres-
ent themselves if more farms were to adopt those practices, technologies, and systems. The
report also identifies knowledge gaps in improving agricultural sustainability and makes
recommendations for future actions aimed at improving agricultural sustainability.
S tatement of Task
The National Research Council Committee on Twenty-First Century Systems Agriculture was tasked to:
1. rovide an overview of the current state of U.S. agriculture in the domestic and world economies, and
describe major challenges to farmers and problems in agricultural production related to the environ-
mental, social, and economic sustainability of agriculture.
2. eview the state of knowledge on farming practices and management systems that can increase the
environmental, social, and economic sustainability of agriculture.
3. dentify factors that influence the adoption of farming practices and systems that contribute to the goals
of increasing agricultural sustainability.
4. rovide an update to the 1989 report's methodology to compare the productivity and economics of dif-
ferent systems and practices at levels of increasing complexity (from the level of individual components
in a farm, to a whole farm, to a regional level).
5. escribe and analyze several case studies (including some from the 1989 report) that illustrate farm-
ing practices and management systems that pursue greater agricultural sustainability. Include general
information about the operation, features of the management systems being used, and indicators of
productivity, environmental, and financial performance. For case studies from the 1989 report, include
a retrospective review of the past performance and the evolution of decision making by those producers
over time.
6. ecommend research and development needs for advancing a systems approach to farming in the
United States, and suggest ways to strengthen federal policies and programs related to improving
agricultural production.
7. valuate the transferability of principles underlying farming systems and practices that could improve
sustainability of different agricultural settings, and develop supportable conclusions and recommenda-
tions to improve the sustainability of agriculture under different natural, economic, and policy condi-
tions in different regional or national settings.
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Sustainability in agriculture is a complex and dynamic concept that includes a wide
range of environmental, resource-based, economic, and social issues. The committee's defi-
nition of sustainable farming does not accept a sharp dichotomy between unsustainable
or sustainable farming systems because all types of farming can potentially contribute to
achieving different sustainability goals and objectives. Ultimately, the committee believes
that sustainability is best evaluated against a range of environmental, economic, and social
goals that reflect the views of diverse groups in society. The most intense controversies
about the relative sustainability of different farming practices or farming systems neces-
sarily take place within the domain of politics because preferences for particular farming
systems reflect the priorities of various stakeholders with different working definitions of
Although a final assessment of the sustainability of any particular farming practice or
system is a social and political act, the committee believes that public debates about im-
proving the sustainability of U.S. agriculture need to be based within a good understanding
of the existing scientific research. Science documents the performance and impacts of dif-
ferent agricultural practices and systems, predicts outcomes likely to result from the use of
different systems, develops indicators to measure progress toward sustainability goals, and
expands the range of technological tools and farming management approaches available.
The issue of water quality illustrates the critical role science plays. Societal concerns about
water quality led to passage of the Clean Water Act, which has resulted in various local,
state, and federal guidelines that require use of "best management practices." Guidelines
are provided for acceptable soil phosphorus upper limits, soil erosion rates, water conser-
vation, tillage practices, pesticide use, and a wide array of other process-type practices, all
of which were determined through extensive scientific research.
This chapter first defines key terms used in later chapters and then discusses concepts
of agricultural sustainability. It identifies the boundaries, or scope, for the overall science
assessment of sustainability. Ultimately, this report focuses on current scientific evidence
about the performance of farming practices and systems that can contribute to moving U.S.
farming systems along a trajectory toward meeting various sustainability goals. Indicators
that can be used to provide quantitative assessment of progress toward sustainability are
also discussed. The structure of the report is outlined at the end of this chapter.
General Definitions
The terms "farming," "agriculture," and "farming systems" can comprise a diverse
range of activities. The definitions of agriculture used in the National Research Council
(NRC) report Investing in Research: A Proposal to Strengthen the Agricultural, Food, and
Environmental System (NRC, 1989a) provide some useful definitions and underscore the
potential breadth of farming-related activities and goals (Box 1-2).
Various crop and livestock enterprises on individual farms can interact in complex
ways with one another and with their surrounding ecosystems (USDA-CSREES, 2007).
Combinations of different activities can generate properties of system behavior that might
not be understood or predicted by looking at each practice individually. That behavior is
manifested at various scales ranging from the field, whole farm, landscape, watershed,
and region. Moreover, every farm is embedded in a particular biophysical environment
that provides opportunities and constraints for using different practices or management
strategies, which shapes the impacts of farming activities on environmental, economic,
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G eneral Definitions
Agriculture encompasses the entirety of the system that grows, processes, and provides food, feed,
fiber, ornamentals, and biofuel for the nation. Agriculture includes the management of natural resources
such as surface water and ground water, forests and other lands for commercial or recreational uses, and
wildlife; the social, physical, and biological environments; and the public policy issues that relate to the
overall system. All activities, practices, and processes of the public and private sectors involved in agricul-
ture and forestry are contained within the system. (Adapted from Investing in Research: A Proposal to
Strengthen the Agricultural, Food, and Environmental System [NRC, 1989a]).
A farm is most correctly used to mean a single, identifiable operational unit that manages natural
resources such as water, forests, and other lands to provide food, feed, fiber, ornamentals, energy, and
a range of environmental and other services. "Any operation that sells at least one thousand dollars of
agricultural commodities or that would have sold that amount of produce under normal circumstances" is
considered a farm by the U.S. Department of Agriculture (USDA) (USDA-ERS, 2008). Every farm is embed-
ded within a temporal and spatially dynamic context (environment) and interacts with the geophysical,
biological, economic, and social variables of that environment. Farms employ a wide range of produc-
tion techniques and strategies known as "farming practices." Farms also use marketing techniques and
A farming system is the mix of crops or animal components, or some combination thereof in a farm,
their arrangement over space and time within the farm, the resources and technologies used in their man-
agement, and the nature and effectiveness of hierarchical relationships both within the farm and with the
ecological, social, economic, and political environments within which it operates. The farming system thus
includes community linkages, market integration, labor relationships, and interaction with a wide array of
other influencing factors.
A farming system type can be defined by any commonalities that one might wish to specify—for
example, rangeland, dryland, irrigated, dairy, field crop, high-value crop—and includes the broad range
of context-specific farming systems within the type.
Food systems and agrifood systems refer to the complex set of actors, activities, and institutions that
link food production to food consumption. Studies of agrifood systems often use a "commodity chain" ap-
proach, where they examine the production, processing, trade, wholesaling, retailing, and consumption of
particular commodities, as well as the upstream and downstream processes that connect the various links
in the chain. These terms differ from farming system in that the primary focus is beyond the farm gate.
Systems agriculture is used to define an approach to agricultural research, technology development,
or extension that views agriculture and its component farming systems in a holistic way. The approach
treats components and processes within and across hierarchical levels and scale with appropriate context,
and gives major importance to interactions among them. The USDA Cooperative State Research, Extension,
and Education Service (CSREES) defines its agricultural systems approaches as follows: "Agricultural enter-
prises—crop or livestock—deal with such concepts as labor supply, marketing, finances, natural resources,
genetic stock, nutrition, equipment and hazards. Although it is possible to effectively manipulate each
mechanism of successful farming individually, better results can often be obtained by treating the farming
operation as a system. The interactions, then, among system components might be more important than
how each component functions by itself. Treating production operations holistically offers greater manage-
ment flexibility, provides for more environmentally and economically sound practices, and creates safer and
healthier conditions for workers and for farm animals." SOURCE: USDA-CSREES (2007).
and social outcomes. This committee also recognizes that farms operate within a complex
market, policy, and community context, and interactions with those institutions and social
systems affect the performance of every type of agricultural system.
Because of the complex interactions at various scales, this committee has chosen to cast
a relatively wide net in its assessment of the performance of different farming practices and
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systems. The ensuing chapters discuss the impact of individual farming practices not only
as individual components of a particular farm enterprise, but also in the context of whole
farming systems and as pieces of a larger farming landscape at the watershed, regional,
or national scale. Although this report discusses how farmers might be affected by op-
portunities and constraints created by the larger agrifood system (see Box 1-2), a detailed
assessment of the overall social, economic, and environmental performance of the food
processing, distribution, and retailing sectors is beyond the scope of this report.
Farming Practices and Systems
At the time that the report Alternative Agriculture (NRC, 1989b) was released, the term
"alternative agriculture" was commonly used to refer to farming approaches (most notably,
organic farming) that appeared to be dramatically different from the dominant or "conven-
tional" farming systems that characterized contemporary crop and livestock production in
the United States. Today such alternatives are more likely to be referred to as "sustainable"
farming, but the phrase is unfortunately ambiguous. Not only do farming enterprises re-
flect many combinations of farming practices, organization forms, and management strate-
gies, but also all types of systems can potentially contribute to achieving various sustain-
ability goals (for individual farmers and for resource use and environmental sustainability
at the landscape scale).
At some level, the distinctions between what some call "conventional" agricultural
systems and a range of alternative systems have some basis in empirical reality in the U.S.
context. The characteristics and examples of practices associated with each system are
summarized briefly in the following sections to clearly define those terms and how they
are used in this report.
Conventional and Industrial Agricultural Systems
Conventional agricultural systems draw from a set of predominant farming practices in
the United States, although conventional farms are diverse in what they produce and in the
specific combination of practices they use. The size of farms using conventional production
methods ranges from small to large. Most agricultural commodities in the United States are
produced in conventional agricultural systems.
• Conventional crop production makes use of synthetic pesticides and herbicides,
and supplements nutrients generated on the farm (manure) with synthetic fertil-
izer to maintain soil fertility. Fields are more frequently planted in few rotations of
marketable crops than left fallow or planted with cover crops. Conventional corn,
soybean, and cotton farms are increasingly planted with seeds that are genetically
engineered to facilitate weed control or to reduce pest losses (and pesticide use).
• Conventional animal production varies depending on the species produced, the size
of livestock inventories, and the amount of cropland or pasture available per ani-
mal unit. Animals might be housed in partial to full confinement structures, with
beef cattle, sheep, and goats being less confined (for at least part of their life cycle),
dairy cows being more confined than sheep and beef cattle, and conventional
hogs and poultry most confined among livestock. Although beef cattle, sheep, and
goat farms rely heavily on pastures, most conventionally raised dairy cows, hogs,
and poultry receive virtually all their feed from harvested forage and grain crops
raised on the farm or purchased from other farmers. Depending on the number of
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animals and the resources of the producers, vaccines, antibiotics, medicated feeds,
and growth hormones could be used in production. Animal manure is spread on
fields or managed in lagoons, with excess liquid sprayed on fields as in the case of
some hog farms.
• Industrial crop and animal production is a term that has come to be associated with
operations that, generally speaking, are characterized by large size combined in
some cases with a high degree of specialization. Producers of industrial scale are
more likely to produce under contract with food processors and handlers. Ani-
mals are more likely to be grown in confined housing, with no pasture in the case
of swine and poultry, or with portions of the animal life cycle on pasture or low
confinement for dairy and beef animals. Feed is more likely to be a purchased in-
put, rather than produced on the farm, than operations of smaller scale. Many of
the larger operations likely have cropped land for liquid manure application, but
loading limits over time rarely allow long-term stability for adequate disposal or
low-rate application for efficient use of water and nutrients. Contract arrangements
often are used for distant application of manure. Industrial farms typically oper-
ate at a scale that allows for more extensive division of labor and the use of capital
intensive machinery and buildings. They more often rely on a hired workforce than
do their smaller-scale counterparts.
Over the last few decades there has been a major effort to develop new management
approaches and farming practices that not only improve the economic performance and
productivity of conventional and industrial farming systems, but also prevent and mitigate
their potentially negative effects on soil erosion and water quality, some of which also can
improve the economic performance and productivity of conventional farming. Examples
of practices used in these strategies are summarized in Box 1-3 and will be discussed in
depth in Chapter 3.
Ecologically Based Farming Systems
Some farming approaches have been developed, at least in part, to respond to per-
ceived problems associated with conventional farming. They represent a concerted depar-
ture from some of the key features of conventional farming such as the reliance on off-farm
and synthetic inputs. Such approaches emphasize the use of natural processes within the
farming system, often called "ecological" or "ecosystem" strategies, which build efficiency
(and ideally resilience) through complementarities and synergies within the field, the farm,
and at larger scales across the landscape and community. Examples of such systems include
organic and biodynamic farming (Box 1-4), although "pure" forms of each system are diffi-
cult to identify. Like conventional farms, the specific practices used could vary widely from
farm to farm, and often include combinations of the practices discussed in Box 1-3.
A Farming Systems Continuum
A dichotomy between "ecologically based" and "conventional" farming systems has
been a component of public debates over the performance of the U.S. farming sector for
several decades. The dichotomy has been a heuristic device that scientists use to explore the
comparative performance of different farming systems. However, in reality, these terms are
to be used with great caution because farming enterprises found in the United States clearly
reflect a potentially infinite set of combinations of particular farming practices, organiza-
tional forms, and management strategies. (See the case studies in Chapter 7.)
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E xamples of Practices Designed to Improve Environmental
P erformance of Conventional Agriculture
• rop rotation, which involves the successive planting of different crops on the same lands in sequen-
tial seasons to improve soil fertility and to avoid the build up of pathogens and pests that often occur
when one species is continuously cropped. The most common rotations involve alternating production
of corn and soybean.
• over crops as part of a crop rotation, which involves the planting of crop varieties that can potentially
protect fields from soil erosion, suppress weeds, and enhance soil organic matter and nutrient levels.
• educed-tillage and no-till practices, in which a crop is planted directly into a seedbed not tilled
since harvest of the previous crop. Instead of plowing soil and burying crop residues, no-till farmers
minimize soil disturbance and leave residues on the surface of their fields after harvest.
• ntegrated pest management (IPM), which involves the strategic use of complementary prac-
tices—including cultural, mechanical, biological, ecological, and chemical control methods—to keep
pest levels below critical economic thresholds.
• recision farming practices, which combine detailed spatial information about soil conditions and
indicators of crop performance to target fertilization and other crop management practices where they
are most needed.
• iversification of farm enterprises, which helps increase biodiversity, control pests and diseases,
and reduce risks from climatic and market volatility.
• ther agricultural conservation best management practices (BMPs), which are recommended
as part of federally funded conservation programs. BMPs include the use of buffer or filter strips, ri-
parian area access management, manure handling and management, nutrient management
planning, wildlife habitat enhancement within agricultural landscapes, composting to process
agricultural wastes, and practices designed to increase irrigation water use efficiency (USDA-NRCS,
• he development of crops and animals that have enhanced genetic resistance to climatic extremes,
pests, and other threats, often with the use of new genetic engineering tools.
E xamples of Ecologically Based Farming Systems
Organic farming systems emphasize the use of renewable resources and the conservation of soil
and water to enhance environmental quality for future generations. They typically rely on crop rotations,
green manures, composts, naturally derived fertilizers and pesticides, biological pest controls, mechanical
cultivation, and modern technology. Organic meat, poultry, eggs, and dairy products come from animals
that are not given any antibiotics or growth hormones. Organic food is produced without the use of most
conventional pesticides, fertilizers made with synthetic ingredients or sewage sludge, bioengineering, or
ionizing radiation. Before a product can be labeled "organic" in the United States, a government-approved
certifier inspects the farm where the food is grown to make sure the farmer is following all the rules neces-
sary to meet USDA organic standards.
Biodynamic farming systems typically use the full range of organic production practices, but also use
a series of eight soil, crop, and compost amendments, called preparations, made from cow manure, silica,
and various plant substances. Biodynamic farming also places greater emphasis on (1) the integration
of animals to create a closed nutrient cycle, (2) using an astronomical calendar to determine auspicious
planting, cultivating, and harvesting times, and (3) an awareness of spiritual forces in nature. Biodynamic
farmers view the soil and the whole farm as an integrated, living organism and self-contained individuality.
More than a production system, biodynamic agriculture is a practice of living and relating to nature in a
way that focuses on the health of the bioregion, landscape, soil, and animal, plant, and human life, and it
promotes the inner development of each practitioner. The Demeter Association has certification programs
for food and feed produced by strict biodynamic farming methods in different countries.
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Moreover, the definitions that once clearly demarcated conventional from ecologically
based farming systems have become muddled. One example is the "conventionalization"
of the organic farming industry in the United States (Guthman, 2004), characterized by the
entry of large-scale farms in the market for USDA-certified organic products. Most farms
present examples of hybrid or intermediate stages on a continuum between the extremes of
agricultural practices, and their adoption of various new practices has produced apparent
gains in environmental performance (Keystone Center, 2009). Some of the "mixed farming
systems" also have been given names (Box 1-5).
The committee concludes that no simple typology or set of categories can capture
the complexity of the farming practices and systems used on diverse U.S. farms. The lack
of a single accepted typology complicated the writing of this report. Because so much of
the research literature is based on comparisons of particular farming practices, or of one
or more of those stylized "farming systems," research findings are cited throughout the
report using the categories described by the scientists who conducted the research. For this
reason, this report cites organic farming systems more frequently than other ecologically
based systems. The illustrative use of organic systems is not intended to imply that organic
E xamples of Mixed Farming Systems
Conservation agriculture is a term used by the United Nation's Food and Agricultural Organization
(FAO) to refer to the use of resource-conserving but high-output agricultural systems. According to the FAO,
conservation farming typically involves the integrated use of minimal tillage systems, cover crops, and crop
rotations (http://www.fao.org/ag/ca/).
Reduced- or low-input farming is based on a reduction of materials imported from outside the
farm, such as commercially purchased chemicals and fuels. Low-input farming employs technologies and
is structured in such a way that tightens flow loops and provides ecosystem services internal to the farm
and field, and therefore reduces input use. Such internal resources include biological pest controls, solar
or wind energy, biologically fixed nitrogen, and other nutrients released from green manures, organic
matter, or soil reserves. Whenever possible, external resources are replaced by resources found on or near
the farm. Many reduced-input or low-input farming systems are examples of integrated farming systems
(see below).
Integrated farming system is a term commonly used in Europe to describe widely adopted pro-
duction systems that combine methods of conventional and organic production systems in an attempt
to balance environmental quality and economic profit. For example, integrated farmers build their soils
with composts and green manure crops but also use some synthetic fertilizers; they use some synthetic or
natural pesticides in addition to biological, cultural, and mechanical pest control practices.
Alternative livestock production systems refer to farms that use lower-confinement housing and
rely more on pastures than conventional and industrial livestock farms. A common example in dairy farm-
ing is the use of intensive rotational grazing practices that involve the use of short duration, intensive
grazing episodes followed by long rest periods that allow pastures or fields to recover.
Mixed crop-livestock farming is characterized by livestock enterprises where a significant fraction
of the animal feed inputs are generated on cropland and pastures that are under the direct control of
the livestock farmer. Those systems capitalize on the ability of the enterprise to use synergies between the
crop and livestock enterprises to efficiently recycle nutrients, promote crop rotations, and insulate livestock
farmers from price fluctuations in feed and input markets. They reflect the resurgence of traditional mixed
crop-livestock farming systems that characterized most production units in the first half of the 20th century.
On the other hand, the scale and sophistication of many 21st century mixed crop-livestock farms reflect
the effects of new technologies, breed improvements, and greater awareness of environmental issues than
their predecessors.
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farming systems are more sustainable than other farming systems. Indeed, all farming
system types have opportunities to improve in sustainability, and all farming system types
could be unsustainable depending on their management and on environmental, social, and
economic changes over time.
Defining Sustainability Goals
In its broadest sense, sustainability has been described as the ability to provide for core
societal needs in a manner that can be readily continued into the indefinite future without
unwanted negative effects. Most definitions of sustainability are framed in terms of three
broad social goals: environmental, economic, and social health or well-being.1 For example,
a sustainable farming system might be one that provides food, feed, fiber, biofuel, and other
commodities for society, as well as allows for reasonable economic returns to producers and
laborers, cruelty-free practices for farm animals, and safe, healthy, and affordable food for
consumers, while at the same time maintains or enhances the natural resource base upon
which agriculture depends (USDA-NAL, 2007).
The legal definition of sustainable farming systems as defined in the Food, Agriculture,
Conservation, and Trade Act (1990 Farm Bill and revised in 2007) is a useful starting point
for identifying sustainability goals for the purposes of this report:
an integrated system of plant and animal production practices having a site-specific appli-
cation that will, over the long term: satisfy human food and fiber needs; enhance environ-
mental quality and the natural resource base upon which the agricultural economy depends;
make the most efficient use of nonrenewable resources and on-farm resources and integrate,
where appropriate, natural biological cycles and controls; sustain the economic viability of
farm operations; and enhance the quality of life for farmers and society as a whole.
This legal definition mingles a description of societal sustainability goals with strategies
that can be used to achieve those goals (for example, "an integrated system which will use,
where appropriate natural biological cycles and controls"; or "make the most efficient use
of nonrenewable and on-farm resources"). This report makes a clear distinction between
societal sustainability goals and the management systems used to pursue these goals. That
distinction recognizes that the same goals can potentially be achieved through a range of
different management and organizational approaches.
Modifying the Farm Bill definition slightly, the committee isolated four key societal
sustainability goals that serve as the organizing principles for the remainder of this report
(Figure 1-1):
• Satisfy human food, feed, and fiber needs, and contribute to biofuel needs.
• Enhance environmental quality and the resource base.
• Sustain the economic viability of agriculture.
• Enhance the quality of life for farmers, farm workers, and society as a whole.
The sustainability of a farming practice or system could be evaluated on the basis of how
well it meets various societal goals or objectives. To be sustainable, a farming system needs
1 In Europe, the three goals of sustainability are sometimes referred to as the 3Ps: people, prosperity, and planet,
or, alternatively, as the "triple bottom line."
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FIGURE - Sustainability goals used in this report. The area where the four goals overlap repre-
sents the highest sustainability in the continuum.
to be robust (that is, be able to continue to meet the goals in the face of stresses and fluctu-
ating conditions; to adapt and evolve), be sufficiently productive, use resources efficiently,
and balance the four goals. There are, however, often tradeoffs or synergies among the
various goals and their related objectives, toward which sustainability is directed.
In the discussions that follow, the scientific evidence surrounding different farming
practices or farming systems that illustrate their ability to further each of these four societal
goals is discussed. The committee is not suggesting or implying that a farming practice
would have to simultaneously accomplish each of these goals to be considered "sustain-
able." Rather, it recognizes and expects that combinations of practices used in a system will
affect each of the four goals in different and often complicated ways. A sustainable system
would balance and meet each of the four goals to a large extent.
Each of the four sustainability goals consists of a large number of more specific objec-
tives that represent different paths toward achievement of the goal. For example, the goal
to "satisfy human food, feed, and fiber needs" requires managing farming systems in the
aggregate so that there will be enough affordable food and fiber (including for energy pro-
duction) in the future for all on the globe, although U.S. production would only play a part
in overall global production. That goal has a long history and is a fundamental concern of
all societies through time and can be summarized with the crucial question: Will there be
sufficient agricultural resources in the future?
Achieving that goal will, at a minimum, require sufficient productivity (for example,
the sheer volume of outputs produced from a given agricultural activity), farming practices
that produce the outputs at a price that consumers can afford, and marketing and distri-
bution systems to ensure that people have ready access to farm products. The concepts of
productivity, affordability, and access represent specific objectives that are required to meet
the overall goal.
Even relatively simple objectives can quickly become more complex. For example,
agricultural productivity over time is influenced by the technologies that are available.
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Sometimes built capital, such as machinery or chemicals, can substitute for natural capital,
such as natural soil fertility. Food productivity has risen over time in the United States, in
part, because of the substitution of fertilizers for natural soil fertility. If the substitution is
viewed as socially acceptable, if fertilizer is affordable and effective, and if its use is not ac-
companied by unwanted or detrimental side effects, then the loss of natural soil fertility as a
result of a farming practice might be viewed as sustainable. If, however, fertilizer is viewed
as a poor substitute for natural fertility, as having important unwanted side effects, or is
thought to be unaffordable or ineffective in the future, then a farming system that results in
losses of natural fertility of the soil will be viewed as unsustainable (Batie, 2008b).
Likewise, each of the other three goals comprise a number of specific objectives. The
objectives listed in Box 1-6 are representative of various objectives associated with sustain-
ability goals, and they are used to organize the review of the scientific literature in Chapters
3, 4, and 5. The specific objective of access to food is not discussed in this report because it
is covered by another report, The Public Health Effects of Food Deserts: Workshop Summary
(IOM and NRC, 2009). Quality and safety of food output is discussed in the context of its
quality and safety at the farm gate. Food processing is beyond the scope of this report.
As the representative objectives listed in Box 1-6 illustrate, the question of the sufficient
quantity of agricultural resources is not the only societal concern underlying calls for more
sustainability. For example, the objectives listed with respect to environmental quality re-
flect a societal concern about the impacts of agriculture on the functional integrity of envi-
R epresentative Objectives Associated with Sustainability Goals
Satisfy human food, feed, and fiber, and contribute to biofuel needs
• Productivity of farming practice or system
• Quality and safety of food output
• Affordability of farm outputs
• Availability of farm outputs
Enhance environmental quality and quality of resource base
• Soil quality and health
• Water quality
• Air quality
• Biodiversity
• Animal health and welfare
Sustain the economic viability of agriculture
• Farm business profitability and viability
• Farm and household viability
• Farm labor economic security
• Community economic security
Enhance the quality of life for farmers, farm workers, and society as a whole
• nsure that farm operators and their households are able to maintain an acceptable quality of life,
including access to health and retirement benefits
• rotect the health and welfare of farmers, farm workers, and society
• nhance community or social well-being from the surrounding agriculture, including access to local
food, sustained provision of ecological services, and maintenance of attractive landscapes
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in the "honest broker" spirit that this committee undertook to review the various scientific
(social and biophysical) literature on sustainable farming systems.
In 1999, the National Research Council's Board on Sustainable Development observed
that the "quest for sustainability will necessarily be a collective, uncertain and adaptive
endeavor in which society's discovering of where it wants to go and how it might try to
get there will be inextricably intertwined" (NRC, 1999, p. 17). That is, sustainability will be
discovered and more clearly defined for agriculture as society experiments with different
farming systems and observes their consequences relative to sustainability goals and makes
legal, institutional, and management adjustments in response. In that sense, sustainable
management of agricultural resources is a journey of discovery and adaptive management,
more than a specific destination.
This committee, thus, regards sustainability as more of a process that moves farming
systems along a trajectory toward meeting various socially determined sustainability
goals (that is, desired outcomes) as opposed to achieving any particular end state. Sus-
tainability goals and strategies used to achieve them are expected to change over time as
more is learned about tradeoffs and societal objectives, and as biophysical or socioeco-
nomic conditions change. For the remainder of this report, those assumptions are used to
guide the scientific review to identify what attributes a farming systems needs to exhibit to
be sustainable (that is, to put agriculture on a sustainable trajectory overtime).
Evaluation of progress toward sustainability in agricultural systems inevitably requires
monitoring of some set of measurements or indicators. The National Research Council's
report, Our Common Journey; a Transition Toward Sustainability, noted the importance of
appropriate monitoring and indicator systems, with indicators being "repeated observa-
tions of natural and social phenomena that represent systematic feedback. They generally
provide quantitative measures of the economy, human well-being, and impacts of human
activities on the natural world" (NRC, 1999, pp. 233–234). Indicators are used to represent
or serve as proxies for the impacts or outcomes of concern. In the policy arena, indicators
can be used to inform the design and implementation of programs and policies.
Figure 1-2 provides an example of the use of indicators in an adaptive management
framework to pursue the broad goal to "enhance environmental quality and the quality
Societal Goals
• Objectives
Evaluation Actions
• Risk A ssessments • Policies
• Adoption of Farming
• Robustness
Systems or Practices
• Indicators
FIGURE - Adaptive management for sustainability of agricultural farming systems.
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of resource base." An example of a specific objective within that goal could be to improve
water quality, which might then be narrowed to one particular water quality concern, such
as nitrogen runoff from corn production that is thought to contribute to hypoxia condi-
tions in the Gulf of Mexico. Decision makers could use information from indicators that
directly or indirectly approximates nitrogen runoff by assessing the area where particular
agricultural practices or farming systems are present. Policy actions could then be based
upon an evaluation of the effectiveness of behavioral changes on nitrogen loading into the
Mississippi River and a multilevel spatial assessment to target efforts in what are found to
be the most critical areas.
Indicators of sustainability presume the existence of goals and objectives, and yet there
is no guarantee that all parties will agree on which sustainability objectives and goals are
desirable or most important, particularly if tradeoffs are involved. As argued previously,
the choice and priority of different goals, and hence use of different indicators, require a
political process involving multiple stakeholders to best serve society. Indeed the authors
of the 1999 NRC report concluded "that there is no consensus on the appropriateness of [a
single] . . . set of indicators or the scientific basis for choosing among them" (NRC, 1999,
p. 243).
Once sustainability objectives are clearly prioritized, indicators are useful for measur-
ing progress toward the desired state as a result of changes to management. There is a large
body of literature devoted to the development, validation, and use of indicators designed
to assist in policy implementation and for conducting research on the relative sustainability
of different farming systems (Rigby et al., 2001; Zhen and Routray, 2003; Bell and Morse,
2008). Conclusions made are predicated on the assumption that the selected indicators ac-
curately reflect how the system is performing, and hence the choice of indicators needs to
be transparent. Each indicator needs to be validated to show that it is a reasonable proxy
for the processes and functions it is meant to represent (Bockstaller and Girardin, 2003).
Because sustainability involves multiple goals and objectives, it is also important to
use a mix of environmental, agronomic, economic, and social well-being indicators when
evaluating the sustainability of whole system performance (Zhen and Routray, 2003; Van
Cauwenbergh et al., 2007). The use of multiple indicators also enables the identification of
tradeoffs and synergies. At present, the bulk of the work on sustainability indicators for
agricultural systems has focused on the first three goals (to satisfy human food and fiber
needs, to enhance environmental quality and the resource base, and to sustain the economic
viability of agriculture), with social indicators for the fourth goal (to enhance the quality of
life for farmers and society as a whole) less developed and researched.
Characteristics and Types of Indicators
Indicators selected need to be appropriate to the sustainability objectives and need to
have the following characteristics:
• Accurately reflective of the process or function it represents.
• Sufficiently sensitive to pick up changes over time and among different farming
• Feasible to measure in terms of time, expense, and level of skill required.
• Understandable and relevant to end-users.
In reality, finding ideal indicators is difficult and compromises have to be made. For ex-
ample, an accurate representation of many system functions (such as nutrient cycling
and retention) requires intensive data collection, monitoring from multiple locations, and
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repetition at appropriate time intervals. Those tasks are expensive, time-consuming, and
require specialized skills. Thus, a spectrum of indicators has emerged that range from
simple, low-cost, means-based indicators to more costly outcome- or effect-based indicators.
Means-based and outcome-based or effect-based indicators fall in different stages along
the cause–effect chain of environmental impacts as a result of farming production practices
(Figure 1-3). Means-based indicators are restricted to description and quantification of prac-
tices, whereas outcome-based (or effects-based, as in Figure 1-3) indicators can be assessed
at a number of steps along the chain, from emissions (for example, what pollutants are
released from the farming operation) to direct measurements of resulting environmental
impacts. Measuring impacts directly seems to be ideal, but it can be difficult and expensive
to accomplish, with considerable uncertainty in assigning cause-and-effect relationships.
Furthermore, some effects might not be detectable for many years, by which time they
might be difficult to reverse. Thus, having good indicators from earlier steps in the cause–
effect chain is essential for taking timely preventive actions. (See Figure 1-4, Payraudeau
and van der Werf [2005] for more detailed discussion of indicator classification.)
An example on nonpoint source pollution helps illustrate the difference between
means-based and outcome-based indicators. Means-based indicators record what practices
and technologies are being used and then rely on previous scientific models to infer the
likely effects of using the practices. For example, it is common to equate the use of recom-
mended BMPs (such as presence of buffer vegetation or use of nutrient budgets, slow
release fertilizers, cover crops, or sufficiency tests) with a standardized coefficient to reflect
FIGURE - Cause–effect chain from farmer production practices to environmental impacts for a
farming region.
NOTE: Pressure indicator is an indicator bitmap
that provides information about anthropogenic stresses
acting on an ecosystem. State indicator is an indicator that provides information about the state of an
ecosystem or specific biota within ecosystems (Payraudeau and van der Werf, 2005).
SOURCE: Payraudeau and van der Werf, 2005. Reprinted with permission from Elsevier.
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expected reductions in nonpoint source pollution. On the other hand, outcome-based or
effects-based indicators require some combination of direct measurement of reductions in
runoff, leaching, levels of nutrients in surface and ground water, or outputs from simula-
tion models.
In some situations, only means-based indicators are feasible and accessible to end
users, particularly for large-scale monitoring for policy and regulatory contexts. Nonethe-
less, caution is to be used when relying on means-based indicators, particularly if changes
measured in such means-based indicators (for example, BMP use) have a more complex
relationship to landscape-scale outcomes than was present in the experimental conditions
used to estimate their original impact coefficients. The most robust means-based indicators
are those with simple causal links derived from a substantial body of evidence compiled
from real-world conditions. A good example is the use of percentage of ground cover as an
indicator of soil erosion potential, a relationship that has been demonstrated many times
across different soil types, slopes, and climates.
There are dangers associated with the use of outcome-based indicators, notably when
effects can be measured, but the causal links to what is actually responsible for causing
the effects are not clear. That particular concern occurs when outcome-based indicators
are used in a regulatory context or for awarding incentives. Using water quality as an
example, changes in nutrient loadings in streams or lakes can be measured directly, but
identifying the cause of the changes can be extremely difficult in the absence of detailed
and comprehensive knowledge of surface or ground water hydrology, pollutant transport,
and in-stream processing of pollutants in the region. Nutrient loadings in streams and
lakes might reflect more of the effects of historical management than of the current one. An
increase in nutrient levels in a section of a stream might not relate to the practices used on
farms immediately adjacent to the stream, but rather to some combination of local input
and loading from subsurface water that contain nutrients derived from a much larger area
within the watershed. In that case, stream nutrient levels would not be a good indicator for
forming the basis of farm-level regulatory decisions.
Means-based and outcome-based indicators can also be developed for measuring the
impacts of farming systems on economic and social sustainability goals. However, there is
typically a small scientific knowledge base to allow an analyst to link the use of particular
production practices or agricultural system with a prediction for economic or social out-
comes. For example, whether adoption of a particular farming practice or system is likely
to increase the economic well-being of farmers and their households might be estimated by
a means-based indicator such as the degree of adoption of a particular practice. However,
to link well-being to that practice might require linking adoption to such factors as reduced
costs of production per unit output. An outcome-based indicator might be to examine levels
of net farm or household income among farms using the practice. Regardless of the indica-
tor selected, complexities in the relationship between use of the practice and accomplish-
ment of the ultimate outcome of improved economic well-being (such as variation in the
management abilities or approaches of individuals, interactions among different cropping
or livestock production activities on a farm, or different marketing outlets) make interpreta-
tion of each type of indicator challenging.
Relating Indicators to Sustainability Goals and System Attributes
The usefulness of indicators can be improved if they are designed to reflect perfor-
mance in terms of a more complete set of systems attributes, including measures of produc-
tivity, resource-use efficiency, and robustness. For example, a commonly used indicator for
the objective of high productivity is crop yield, typically average yield per acre. However
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a more complete indicator would also include assessment of system robustness (such as
a measure of variability in yields over space and time, or the probability of yields falling
below a certain threshold) and of resource-use efficiency of the system as measured by nu-
trient, fertility, water, and energy use expressed per unit crop yield. Similarly, measures of
biodiversity could be improved by incorporating considerations of productivity (number of
species supported and their population sizes), robustness (fluctuations in population sizes,
and the number of extinctions and invasions over space and time), and system efficiency
(for example, the amount of land and water used to support a given number of species and
In the case of social goals, such as increasing community social and economic well-
being, it would be valuable not only to examine productivity in terms of the ability of an
agricultural system to produce desired outcomes (for example, increased net farm income,
improved availability of affordable quality food, and decreases in income inequality), but
also to pay attention to the robustness (stability of outcomes in the face of changing bio-
physical, market, and policy circumstances).
Interpreting Indicators
Indicator values have to be interpreted to be meaningful: that is, significance needs to
be assigned to an indicator's numerical (or qualitative) value. Threshold values have not
been established for many environmental indicators. Conclusions are typically drawn on
the basis of whether numerical values are higher or lower than before, and rarely in terms
of whether the differences are likely to be functionally significant. For example, measures
of soil organic matter are a cornerstone of most sustainability and soil quality assessments,
being seen as an integrative indicator for soil properties such as moisture-holding capacity,
physical structure, and nutrient supply capacity. However, the numerical level that would
be considered good, or what change in soil organic matter levels constitutes a significant
functional change, has not been established (Loveland and Webb, 2003). In contrast, nutri-
ent concentration thresholds for ecological integrity have been established for some fresh-
water lakes (Carpenter and Lathrop, 2008), but no such thresholds for ecological integrity
currently exist for nitrate or phosphorus concentrations in freshwater streams. Clearly,
improving the understanding of the relationships between sustainability indicators and
their functional significance is a priority for future work.
Integrating Diverse Indicators in Holistic Assessments
Using even well-designed indicators still begs the question of how to make a holistic
assessment of the relative sustainability of different systems given the multiple indicators
that represent various sustainability goals and objectives. Even a single sustainability goal,
such as enhancing environmental quality, contains many subobjectives, such as water qual-
ity, air quality, water use, and biodiversity conservation, each of which may be measured
by multiple indicators. One practice is to combine individual indicators into an index,
based on some additive (often weighted) procedure. A single index, however, obscures the
values inherent in its calculation—which attributes are weighted more than others—and
can be particularly problematic if the direction of change is positive for some measures
but negative for others (Suter, 1993; Fisher et al., 2001). Despite that issue, reducing mul-
tiple indicators into a single indicator is done in some policy contexts, such as the use of
an environmental benefits index to implement the Conservation Reserve Program of the
Farm Bill.
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An alternative is to evaluate system performance without creating a single number, in
which case any tradeoffs or synergies might be identified. For example, the same suite of
indicators is monitored over time across all countries and regions in EU, making it possible
to look at the spatial distribution of relative importance of different sustainability issues
and where trends are positive or negative (European Environment Agency, 2006). Data
show that soil erosion and water overdrafts are most serious in the Mediterranean coun-
tries, whereas nitrate pollution is greatest in northern Europe. However, positive nitrogen
balances are declining in most countries where the problems are most severe (for example,
the Netherlands) and have decreased by 16 percent across the EU as a whole between 1990
and 2000. Other indicators used include greenhouse-gas emissions, changes in biodiversity,
and landscape patterns. (See European Environment Agency [2006] for the complete list.)
Those findings are then integrated into the various policy directives and used to evaluate
program effectiveness.
Programs on indicators have been developed by other institutions, including the FAO
(Tschirley, 1997), United Nations (United Nations, 2007), World Bank (Dumanski et al.,
1998), USDA (USDA-ERS, 2003), various university programs in the United States (Aistars,
1999), and such nonprofit organizations as the International Institute of Sustainable Devel-
opment (Pintér et al., 2005) and the Land Stewardship Project (Keeney and Boody, 2005).
Although the proliferation of programs to develop indicators reflects the growing interest
in quantification and evaluation of the sustainability of agriculture, there is not an align-
ment or consensus among the different organizations and scientists involved about the
most appropriate or useful set of indicators. In other words, there are different interpreta-
tions, methods, and approaches for developing and using indicators. Collaborative ef -
forts among different organizations to develop agreement about key indicators needed for
measuring sustainability—and particularly performance outcomes—have emerged in the
U.S. agriculture sector, such as Field to Market: The Keystone Alliance for Sustainable Agri-
culture (Keystone Center, 2009) and the Stewardship Index Initiative for Specialty Crops
(Stewardship Index for Specialty Crops, 2009). Some university programs in the United
States have also convened and attempted to collaborate in the development of indicators
(for example, the Sustainable Agriculture Research and Education Program at University
of California).
It should be noted, however, that the conclusions reached by the different methods can
vary substantially even when applied to the same system (for example, van der Werf et al.,
2007). Those differences emphasize the need for careful assessment of the assumptions
behind each method and for more method comparison studies to be done.
• Sustainable agriculture can involve a diverse number of possible farming practices or
farming systems. The committee's definition of sustainable farming does not accept a
sharp dichotomy between conventional and sustainable farming systems, not only be-
cause farming enterprises reflect many combinations of farming practices, organization
forms, and management strategies, but also because all types of systems can potentially
contribute to achieving various sustainability goals and objectives.
• Sustainability is a process that moves farming systems along a trajectory toward meet-
ing societal defined goals, as opposed to any particular end state. As such, management
systems will inevitably need to be adjusted to meet sustainability goals and objectives
when circumstances and societal desires change.
• Sustainability of agriculture is a complex and dynamic concept. The committee rec-
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ognizes that the concept is inherently subjective in that the goals will be viewed in
different ways by various groups in society. Further, even with broad agreement for
certain goals, the relative importance assigned to one goal over another will be highly
contested. The definition of societal goals for sustainable agriculture emerges from the
domain of politics, not science. Yet, science plays essential roles by generating knowl-
edge to inform the political process, making predictions about outcomes likely to result
from different management systems, answering specific questions when needed, and
expanding the range of alternatives considered. Science also can supply the knowledge
needed to develop new agricultural technologies.
• Finding ways to measure progress along a sustainability trajectory is an important part
of an experimentation and adaptive management process. The rationale for selecting
the indicators used to measure progress needs to be explicitly stated and justified since
the choice is a political rather than a scientific question.
• It is important that indicators used are shown to be appropriate surrogates for the sus-
tainability outcomes they are meant to represent, especially in the case of means-based
• Social indicators, in addition to environmental and economic measures, will help pro-
vide a more comprehensive assessment of movement toward sustainability goals; how-
ever, much more research is needed to develop appropriate social indicators because
the development of such measures to date has been fledgling.
Using the terms and the boundaries defined in this chapter, this report provides an
overview of how U.S. agriculture has evolved over the years to the current state, and
farmers' successes and the challenges they face (Chapter 2). The state of knowledge on
farming practices and management systems that can increase the environmental and pro-
duction (Chapter 3), social, and economic (Chapter 4) sustainability of agriculture are
then discussed. However, individual farming practices are components of an agricultural
system. Knowledge and understanding of the sum of the parts are important in design-
ing, fine-tuning, and adapting the system to improve sustainability. Chapter 5 uses a few
systems to illustrate how a collection of farming practices works in concert to improve
sustainability and to illustrate some potential tradeoffs. In spite of the positive attributes of
some farming practices and systems that can improve sustainability, they are not necessar-
ily widely adopted by farmers. Chapter 6 highlights the importance of markets, policies,
and research in shaping trajectories of farm change, and examines influences on farmers
that make some of them more likely and able than others to change production practices or
convert to new farming systems. The approaches that could improve environmental, social,
and economic sustainability, their practical applications, and their ability to meet those
goals are best illustrated in examples of real-life farms in Chapter 7. The committee used
seven farms featured in the report Alternative Agriculture (NRC, 1989b) and nine additional
farms as case studies to illustrate points made earlier in the report. Conclusions drawn
in earlier chapters were used as the basis of the discussion on the lessons learned in U.S.
agriculture that are relevant to agriculture in other regions in Chapter 8. A representative
of the Gates Foundation specified that the foundation was most interested in the relevance
of lessons learned to sub-Saharan Africa, which is the focus of Chapter 8. The committee's
findings and recommendations for how to advance a systems approach to farming and to
strengthen federal policies and programs related to improving agricultural production in
the United States are summarized in Chapter 9.
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Adger, W.N. 2006. Vulnerability. Global Environmental Change 16:268–281.
Aistars, G.A. 1999. A life cycle approach to sustainable agriculture indicators. Available at http://css.snre.umich.
edu/css_doc/Proceedings.PDF. Accessed on May 20, 2009.
Atwill, E.R. 2008. Implications of wildlife in E. coli outbreaks associated with leafy green produce. Paper read at
23rd Vertebrate Pest Conference, San Diego.
Batie, S. 2008a. Wicked problems and applied economics. American Journal of Agricultural Economics 9(5):
Batie, S.S. 2008b. The sustainability of U.S. cropland soils. In Perspectives on Sustainable Resources in America,
R.A. Sedjo, ed. Washington, D.C.: RFF Press.
Bell, S., and S. Morse. 2008. Sustainability Indicators: Measuring the Immeasurable. London: Earthscan.
Bockstaller, C., and P. Girardin. 2003. How to validate environmental indicators. Agricultural Systems 76(2):
Boody, G., B. Vondracek, D.A. Andow, M. Krinke, J. Westra, J. Zimmerman, and P. Welle. 2005. Multifunctional
agriculture in the United States. BioScience 55(1):27–38.
Brown, C., and U. Lall. 2006. Water and economic development: the role of variability and a framework for resil-
ience. Natural Resources Forum 30 (4):306–317.
Carpenter, S.R., and R.C. Lathrop. 2008. Probabilistic estimate of a threshold for eutrophication. Ecosystems 11(4):
Chapin, F.S., G.P. Kofinas, and C. Folke (eds.) 2009. Principles of Ecosystem Stewardship: Resilience-based Natural
Resource Management in a Changing World. New York: Springer.
Collins, K. 2008. The role of biofuels and other factors in increasing farm and food prices—a review of recent devel-
opments with a focus on feed grain markets and market prospects. Available at http://www.foodbeforefuel.
org/files/Role%20of%20Biofuels%206-19-08.pdf. Accessed on June 8, 2009.
Conway, G.R. 1987. The properties of agroecosystems. Agricultural Systems 24(2):95–117.
Crumpton, W.G., D.A. Kovacic, D.L. Hey, and J.A. Kostel. 2008. Potential of Restored and Constructed Wetlands
to Reduce Nutrient Export from Agricultural Watersheds in the Corn Belt. St. Joseph, Mich.: ASABE.
Dobbs, T.L. 2008. Economic and policy conditions necessary to foster sustainable farming and food systems:
U.S. policies and lessons from the European Union. Available at http://www.foodandsocietyfellows.org/
publications.cfm?refID=104050. Accessed on August 6, 2009.
Doyle, M.P., and M.C. Erickson. 2008. Summer meeting 2007—the problems with fresh produce: an overview.
Journal of Applied Microbiology 105(2):317–330.
Dumanski, J., E. Terry, D. Byerlee, and C. Pieri. 1998. Performance indicators for sustainable agriculture. Available
at http://siteresources.worldbank.org/INTARD/864477-1112703179105/20434502/SustInd.pdf. Accessed
on May 20, 2009.
Eakin, H., and A.L. Luers. 2006. Assessing the vulnerability of social-environmental systems. Annual Review of
Environment and Resources 31:365–394.
Ebi, K.L., R.S. Kovats, and B. Menne. 2006. An approach for assessing human health vulnerability and public
health interventions to adapt to climate change. Environmental Health Perspectives 114(12):1930–1934.
European Environment Agency. 2006. Integration of Environment into EU Agricultural Policy—the IRENA
Indicator-Based Assessment Report. Copenhagen: European Environment Agency.
Fisher, W.S., L.E. Jackson, G.W. Suter, and P. Bertram. 2001. Indicators for human and ecological risk assessment: a
US Environmental Protection Agency perspective. Human and Ecological Risk Assessment 7(5):961–970.
Folke, C. 2006. Resilience: the emergence of a perspective for social-ecological systems analyses. Global Environ-
mental Change—Human and Policy Dimensions 16(3):253–267.
Folke, C., S. Carpenter, T. Elmqvist, L. Gunderson, C.S. Holling and B. Walker. 2002. Resilience and sustainable
development: building adaptive capacity in a world of transformations. Ambio 31(5): 437–440
Fowler, H.J., C.G. Kilsby, and P.E. O'Connell. 2003. Modeling the impacts of climatic change and variability on the
reliability, resilience, and vulnerability of a water resource system. Water Resources Research 39(8):1222.
Goldstein, B.E. 2009. Resilience to surprises through communicative planning. Ecology and Society 14(2):33. Avail-
able at http://www.ecologyandsociety.org/vol14/iss2/art33/. Accessed on March 3, 2010.
Guthman, J. 2004. Agrarian Dreams: The Paradox of Organic Farming in California. Berkeley: University of Cali-
fornia Press.
Holling, C.S. 1996. Surprise for science, resilience for ecosystems, and incentives for people. Ecological Applications
———. 2001. Understanding the complexity of economic, ecological, and social systems. Ecosystems 4:390–405.
IOM (Institute of Medicine) and NRC (National Research Council). 2009. The Public Health Effects of Food
Deserts. Workshop Summary. Washington, D.C.: National Academies Press.
OCR for page 15
Janssen, M.A., M.L. Schoon, W.M. Ke, and K. Borner. 2006. Scholarly networks on resilience, vulnerability and
adaptation within the human dimensions of global environmental change. Global Environmental Change—
Human and Policy Dimensions 16(3):240–252.
Josling, T. 2002. Competing paradigms in the OECD and their impact on the WTO agricultural talks. In Agricul-
tural Policy for the 21st Century, L. Tweeten and S.R. Thompson, eds. Ames: Iowa State Press.
Keeney, D., and G. Boody. 2005. Performance based approaches to agricultural conservation programs dealing
with non-point source pollution, including utilization of the provisions of the conservation security program.
Available at http://www.landstewardshipproject.org/mba/performance_based_policies.pdf. Accessed on
August 10, 2009.
Keystone Center. 2009. Field to market: the Keystone Alliance for Sustainable Agriculture. Available at http://
www.keystone.org/spp/environment/sustainability/field-to-market. Accessed on August 10, 2009.
Loveland, P., and J. Webb. 2003. Is there a critical level of organic matter in the agricultural soils of temperate
regions: a review. Soil & Tillage Research 70(1):1–18.
Milestad, R., and I. Darnhofer. 2003. Building farm resilience: the prospects and challenges of organic farming.
Journal of Sustainable Agriculture 22(3):81–97.
Naylor, R.L. 2008. Managing food production systems for resilience. In Principles of Natural Resource Steward-
ship: Resilience-Based Management in a Changing World, F.S. Chapin, G.P. Kofinas, and C. Folke, eds. New
York: Springer.
Nelson, D.R., W.N. Adger, and K. Brown. 2007. Adaptation to environmental change: contributions of a resilience
framework. Annual Review of Environment and Resources 32:395–419.
NRC (National Research Council). 1989. Investing in Research: A Proposal to Strengthen the Agricultural, Food,
and Environmental System. Washington, D.C.: National Academy Press.
———. 1989b. Alternative Agriculture. Washington, D.C.: National Academy Press.
———. 1996. Understanding Risk: Informing Decisions in a Democratic Society. Washington, D.C.: National
Academy Press.
———. 1999. Our Common Journey: A Transition Toward Sustainability. Washington, D.C.: National Academy
Payraudeau, S., and H.M.G. van der Werf. 2005. Environmental impact assessment for a farming region: a review
of methods. Agriculture Ecosystems & Environment 107(1):1–19.
Pielke, R.A., Jr. 2007. The Honest Broker: Making Sense of Science in Policy and Politics. New York: Cambridge
University Press.
Pintér, L., P. Hardi, and P. Bartelmus. 2005. Sustainable Development Indicators: Proposals for a Way Forward.
Winnipeg: International Institute for Sustainable Development.
Rigby, D., P. Woodhouse, T. Young, and M. Burton. 2001. Constructing a farm level indicator of sustainable agri-
cultural practice. Ecological Economics 39(3):463–478.
Robledo, C., M. Fischler, and A. Patino. 2004. Increasing the resilience of hillside communities in Bolivia—has
vulnerability to climate change been reduced as a result of previous sustainable development cooperation?
Mountain Research and Development 24(1):14–18.
Santelmann, M.V., D. White, K. Freemark, J.I. Nassauer, J.M. Eilers, K.B. Vache, B.J. Danielson, R.C. Corry, M.E.
Clark, S. Polasky, R.M. Cruse, J. Sifneos, H. Rustigian, C. Coiner, J. Wu, and D. Debinski. 2004. Assessing
alternative futures for agriculture in Iowa, USA. Landscape Ecology 19(4):357–374.
Searchinger, T., R. Heimlich, R.A. Houghton, F. Dong, A. Elobeid, J. Fabiosa, S. Tokgoz, D. Hayes, and T-H. Yu.
2008. Use of U.S. croplands for biofuels increases greenhouse gases through emissions from land use change.
Science 319:1238–1240.
Stewardship Index for Specialty Crops. 2009. Welcome to the homepage of the Stewardship Index for Specialty
Crops. Available at http://www.stewardshipindex.org/. Accessed on August 10, 2009.
Suter, G.W. 1993. A critique of ecosystem health concepts and indexes. Environmental Toxicology and Chemistry
Thompson, P.B. 2010. The Agrarian Vision: Sustainability and Environmental Ethics. Lexington: University of
Kentucky Press.
Tokgoz, S., A. Elobeid, J. Fabiosa, D.J. Hayes, B.A. Babcock, T.H. Yu, F.X. Dong, and C.E. Hart. 2008. Bottlenecks,
drought, and oil price spikes: impact on U.S. ethanol and agricultural sectors. Review of Agricultural Econom-
ics 30(4):604–622.
Tschirley, J.B. 1997. The use of indicators in sustainable agriculture and rural development: considerations for
developing countries. In Sustainability Indicators, B. Moldan and S. Billharz, eds. New York: John Wiley
and Sons.
OCR for page 15
Turner, B.L., R.E. Kasperson, P.A. Matson, J.J. McCarthy, R.W. Corell, L. Christensen, N. Eckley, J.X. Kasperson,
A. Luers, M.L. Martello, C. Polsky, A. Pulsipher, and A. Schiller. 2003. A framework for vulnerability analy-
sis in sustainability science. Proceedings of the National Academy of Sciences of the United States of America
United Nations. 2007. Indicators of sustainable development: guidelines and methodologies. Available at http://
www.un.org/esa/sustdev/natlinfo/indicators/guidelines.pdf. Accessed on May 20, 2009.
USDA-CSREES (U.S. Department of Agriculture Cooperative State Research, Extension, and Education Ser -
vice). 2007. Agricultural systems overview. Available at http://www.csrees.usda.gov/nea/ag_systems/
ag_systems.cfm. Accessed on October 29, 2008.
USDA-ERS (U.S. Department of Agriculture Economic Research Service). 2003. Agricultural resources and envi-
ronmental indicators, 2003. Available at http://www.ers.usda.gov/publications/arei/ah722/dbgen.htm.
Accessed on May 20, 2009.
———. 2008. Farm income: partitioning the definition of a farm. Available at http://www.ers.usda.gov/data/
farmincome/Sizedefinition.htm. Accessed on September 24, 2009.
USDA-NAL (U.S. Department of Agriculture National Agricultural Library). 2007. Sustainable agriculture: defi-
nitions and terms. Available at http://www.nal.usda.gov/afsic/pubs/terms/srb9902.shtml. Accessed on
August 10, 2009.
USDA-NRCS (U.S. Department of Agriculture National Resource Conservation Service). 2009. National conserva-
tion practice standards. Available at http://www.nrcs.usda.gov/technical/standards/nhcp.html. Accessed
on September 10, 2009.
Van Cauwenbergh, N., K. Biala, C. Bielders, V. Brouckaert, L. Franchois, V.G. Cidad, M. Hermy, E. Mathijs, B.
Muys, J. Reijnders, X. Sauvenier, J. Valckx, M. Vanclooster, B. Van der Veken, E. Wauters, and A. Peeters.
2007. SAFE—a hierarchical framework for assessing the sustainability of agricultural systems. Agriculture
Ecosystems & Environment 120(2–4):229–242.
van der Werf, H.M.G., J. Tzilivakis, K. Lewis, and C. Basset-Mens. 2007. Environmental impacts of farm scenarios
according to five assessment methods. Agriculture Ecosystems & Environment 118(1–4):327–338.
Walker, B., and D. Salt. 2006. Resilience Thinking. Washington, D.C.: Island Press.
Zhen, L., and J.K. Routray. 2003. Operational indicators for measuring agricultural sustainability in developing
countries. Environmental Management 32(1):34–46.
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Further education (often abbreviated "FE", called continuing education in U.S. English) is a term mainly used in connection with education in the United Kingdom and the Republic of Ireland. It is post-compulsory education (in addition to that received at secondary school), that is distinct from the education offered in universities (higher education). It may be at any level above compulsory education, from basic training to Higher National Diploma or Foundation Degree. A distinction is usually made between FE and higher education ("HE") which is education at a higher level than secondary school, usually provided in distinct institutions such as universities. FE in the United Kingdom therefore includes education for people over 16, usually excluding universities. It is primarily taught in FE colleges (which are similar in concept to United States community colleges, and sometimes use "community college" in their title), work-based learning, and adult and community learning institutions. (Excerpt from Wikipedia article: Further education)
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Towards a Pragmatic Framework for Accessible E-Learning |
Lawrie Phipps, Neil Witt and Brian Kelly while recognising the importance of accessibility in e-learning resources, query the universal applicability of the Web Accessibility Initiative's guidelines and describe a pragmatic framework which provides a broader context for their use. |
July 2005, issue44, feature article |
Developing and Publicising a Workable Accessibility Strategy |
Lawrie Phipps, Sue Harrison, David Sloan and Betty Willder look at the increasing need for developers of institutional and educational Web sites to develop and follow a strategy for ensuring optimal accessibility of online content. |